SDN-Based Data Offloading for 5G Mobile Networks

The rapid growth of 3G/4G enabled devices such as smartphones and tablets in large numbers has created increased demand for mobile data services. Wi-Fi offloading helps satisfy the requirements of data-rich applications and terminals with improved multi- media. Wi-Fi is an essential approach to alleviating mobile data traffic load on a cellular network because it provides extra capacity and improves overall performance. In this paper, we propose an integrated LTE/Wi-Fi architecture with software-defined networking （SDN） abstraction in mobile baekhaul and enhanced components that facilitate the move towards next-generation 5G mo- bile networks. Our proposed architecture enables programmable offloading policies that take into account real-time network conditions as well as the status of devices and applications. This mechanism improves overall network performance by deriving real- time policies and steering traffic between cellular and Wi-Fi networks more efficiently.

Channel measurement and modeling for the 15-GHz radio band in an indoor corridor environment

Traditional mobile communication systems mainly work on the licensed frequency band near or below 3 GHz;however,this band is becoming increasingly crowded.On the other hand,there are abundant unlicensed spectrum resources in higher frequency bands,e.g.,6 GHz,15 GHz,and 28 GHz,and if those bands are applied,the current spectrum shortage problem could be effectively alleviated.However,the wireless channel characteristics and models are important but still unknown,and thus in this study,extensive measurements and modeling have been conducted to study the characteristics of the high-frequency 15-GHz band.Specifically,a PN(Pseudo Noise)sequence based time-domain measurement system was built and applied to measure the propagation characteristics of the LOS(Line-of-Sight)and NLOS(Non-Line-of-Sight)scenarios in an indoor corridor at 15 GHz.Then,in-depth analysis and modeling on the large-scale characteristics of wireless channels,the relationship between distance and path loss,the path loss exponent,and the shadow fading standard variance are provided.Moreover,the relationship between received power and different elevation angles was studied.In the measurement,two 25-dBi horn antennas with a 10 half-power beam width are used to change elevation angles in the transmitting terminal and azimuth angles in the receiving terminal for all measurement points.The findings and results in this work will serve as a reference and basis for future theoretical studies of the 15-GHz band.